The present invention relates generally to an apparatus and method for shaping dough. In particular, it relates to an apparatus and method for cutting a sheet of dough and positioning the cut portion in a pan.
A wide variety of processes are known for forming dough for use in the manufacture of baked goods. Commercially baked goods are commonly produced in large quantities, and are manufactured on a production line. Examples of dough-based baked goods which are formed on a production line include pizza crust, pie crusts, pastries, breads, rolls, and cookies.
There are many known commercial processes for shaping dough. Two of them are particularly suitable for shaping elastic doughs, such as pizza dough. The first process is known as pressing, and the second process is known as sheeting and/or die cutting.
The first process (pressing) includes forming dough into small segments, and using a press to compress and form the dough in a mold. The dough may be formed into either a substantially flat shape, or a more complex, three dimensional shape. Pressing can be used to handle a wide variety of doughs, such as pastry dough, for example. This type of process is not as suitable for processing doughs which are elastic--which tend to have snap back characteristics.
"Snap back" for purposes of this disclosure is a characteristic of dough which is caused by the elasticity of the dough. After stretching, the dough retracts somewhat. For example, when shaping pizza dough by hand, it is common to toss the flattened dough in the air, and cause the disc shaped dough to spin in order to aid in stretching the dough. When the stretched dough is placed in the pan, the overall diameter shrinks, or snaps back.
The second process, known in the art as sheeting, is used in processing doughs having more elastic characteristics. A wide variety of pizza doughs, for example, bread-type pizza doughs are commonly processed by sheeting. Although the sheeting process is used in a wide variety of applications, known processes for forming pizza dough will be described as examples of the sheeting process.
One known process of sheeting pizza dough includes the steps of placing the formed dough on a continuous conveyor belt, and passing the dough through a series of rollers. The rollers transform the dough into a continuous strip, having a uniform thickness and width. The rollers may have a smooth outer surface, or may have an irregular outer surface. Optionally, rollers may be used to knead the dough in a direction transverse to the direction of travel of the conveyor belt. The sheet is sent through a series of rollers, each roller flattening the sheet into a wider, thinner sheet.
After the sheet of dough is rolled into a continuous strip, the dough may pass through a preproofer to increase the strength of the sheet. Preproofing involves exposing the sheet to an elevated temperature and a high humidity environment for a period of time sufficient to change the characteristics of the dough, such as making the dough sheet stronger. The strengthened sheet is next cut by passing the sheet beneath a cutting roller.
The cut portions of the dough, and the waste dough remain on a first conveyor belt during the cutting step. A second conveyor belt lifts the waste dough off of the first conveyor belt, and the cut and now separated portions remain on the first conveyor belt.
The cut portions either remain on the belt during further processing, or may be removed and placed in a container such as a pan for further processing steps. On the belt or in the pan, the cut portions may be proofed, proofed if previously preproofed, or fed directly into an oven. If proofing is desired, the conveyor belt containing the cut portions passes through a proofer having an elevated temperature and high humidity environment, where the leavening and/or yeast in the cut pieces acts on the dough. The humidity level, temperature and dwell time of the dough in the proofer in large part determine the ultimate characteristics of the cooked crust.
The cut portions alone or the cut portions in pans are transferred onto another conveyor, which feeds into an oven for either partial or complete baking. Alternatively, the proofed portions may be delivered to a fryer for deep fat frying.
Another known method of forming a baked pizza crust includes cutting the sheet of dough with a cutting roller, removing the waste dough from the conveyor, removing each cut portion from the conveyor and dropping each cut portion of dough into a pan. This procedure is commonly used when the dough is to be baked in a pan, or when it is desirable to form a baked product with an upstanding outer edge.
When cutting dough formed by sheeting, it is known in the art to alter the shape of the cutting edge to compensate for tension or snap back in the sheet of dough. For example, with an elastic dough such as pizza dough, the cutting edge used for forming a circular pizza crust must be oval. That is, the cut portion must be slightly longer in the direction of travel of the conveyor to compensate for tension in the dough sheet.
In the process now under discussion, a first conveyor transports the cut portions toward the pan. Beneath the first conveyor is a second conveyor which delivers the pans. A sensing device positions the cut portion above the cavity of the pan. There are many known means of positioning a cut portion above a pan. One type of device employs the use of electronic sensors. As the pan approaches, a first electric eye finds a selected location of the cavity in the pan. A second electric eye finds the selected location of the cut portion.
The cut portion is transferred to a nose conveyor which retracts as the cut portion advances toward the leading edge of the nose conveyor. The electronic eye which senses the position of the cut portion retracts the nose conveyor when the second sensor indicates that the pan is beneath the cut portion.
The speed of the conveyor belt, the accuracy and time delay of the sensors, and the placement of the nose bar, are among the variables which determine whether the dough is ultimately centered in the cavity of the pan. Accuracy of placement using the described method is low, and adjustments to the position of dough in the pan without tearing or distorting the dough is difficult. Inaccurate placement in the pan results in waste and in a higher ratio of recycled dough to fresh dough fed into the process.
When forming products such as a deep dish pizza crust having a thick, upstanding outer edge, pans with at least one cavity having substantially vertical, or frustaconical sidewalls are used. Inaccurate placement of the dough in such a pan results in a product which is typically unacceptable to the consumer. The crust may be very upstanding and thick along one edge, and substantially flat at the opposite edge. This type of crust may also exceed the maximum product height, and not fit into the product packaging. A less critical defect occurs with a crust having an outer edge of varying height. In this case, the product is less uniform in appearance, and is perceived by customers to be of a lower quality, as compared to the quality of pizza crusts having edges of a uniform height.
Of course, if the pan is substantially flat, the placement of the cut portions is less critical.
Another known method of placing sheeted dough in a pan is to drape the sheet of dough over the pan, and pass the pan below one or more cutting rollers. The pan and draped sheet pass under a cutting roller that rolls across and is in contact with the upper edge of the pan. The uppermost edge of the pan in combination with the cutting roller severs the sheet of dough, and the cut portion of the dough falls directly into the pan. Although this method centers the cut portion accurately in the pan, the method does not adequately compensate for tension in the dough, and therefore the dough shrinks (snaps back) in the dimension parallel to the direction of travel of the conveyor. For example, when draping dough and cutting the dough over a round pan, the dough snaps back after cutting, forming a finished crust having an oval shape which is undesirable.
In addition to the above, cutting the dough with the upper edges of the pan is not desirable when manufacturing products with thicker and more upstanding outer edges, such as a deep dish pizza crust, or a pie crust. After the dough is cut along the upper edges of the pan, the dough relaxes, and the edges contract. If the dough is highly elastic, or has a high degree of tension, the cut portion shrinks, and the edges do not extend upward along the sidewalls of the cavity in the pan. The cooked product lacks an upstanding, thick outer edge. A similar result is obtained with any dough and essentially perpendicular pan sidewalls.
If the dough is less elastic, or the tension has been reduced, the edges of the dough may extend only partially up the sidewalls of the cavity. The cooked product in this case has a smaller outer edge, and a more flat overall profile than if the dough were cut into a portion larger than the area defined by upper edge of the pan. A similar result is obtained when the sidewall of the pan cavity is sharply angled.